Reason three:The promise of waste-funded tax cuts. The fiscal conservatives and the small state conservatives may both be happy soon – reinforcing reason two. Fiscal conservatives will be happy at George Osborne’s insistence that borrowing can’t get any bigger. Small government conservatives (and supply-siders) can be encouraged that Oliver Letwin’s review suggests a renewed concern about the wastefulness and inefficiency of Labour’s bloated state.

Reason four: The growing clarity of the Tories’ electoral message. That message has just been delivered very powerfully by David Cameron in the Commons, responding to the PM’s statement on the G20 summit…

Three themes stood out:

If Britain is so well-prepared why will our economy shrink faster than all our major competitors according to the IMF and the EU? Cameron said that Gordon Brown was beginning to sound "ridiculous" blaming everything on America.

Britain he said had a weak currency because it had a weak economy and a weak government. After using these words David Cameron revealed they were actually Gordon Brown’s from the past.

Higher taxes are Labour’s secret agenda. Labour’s borrowing bombshell will become a tax bombshell soon. £30bn of borrowing will become a £1,500 bill in higher income tax in future years. "Tax cuts should be life, not just for Christmas".

There is plenty of material in those three points for some very hard-hitting political campaigning.